You will have no problem with this. I ran a half marathon in 1:38 (my only one), and I ran a marathon in 3:40, and would have done it in 3:30 if I hadn’t had a little problem in the last 4 miles. The key for me was the confidence building long runs, doing 15 miles at 7:30 a mile, and then putting in a couple 20-milers at an 8 minute pace. Also, some people say you have to run a full marathon before doing one, but I never ran longer than 20 miles before I did my marathon. Good luck and let us know how you do! I will be training for my second marathon in 2005 as well.